Italian ryegrass is still a significant problem in many Tennessee fields due to failed herbicide burndown applications.

Our recent research suggests that there are two critical factors in burning down ryegrass. First, timing of herbicide application is extremely critical to gain the most consistent ryegrass control.  The second is herbicide choice.

Timing is a very important component in ryegrass control.  Our recent research has shown that burndown applications applied in early February provide better control than the same application in March and is worlds better than applications in April (Picture 1.)

In general, clethodim is the most consistent choice to control this weed.  Glyphosate at best will only provide ryegrass suppression.  The tankmix of the two often will enhance the consistency of ryegrass control.

There have been calls this spring about ryegrass that has escaped multiple clethodim applications.  The concern of course is that resistance has developed as it has in Louisiana and Mississippi.  We plan to conduct a survey this year to determine if resistance to clethodim is present in Tennessee ryegrass.